Ali. A. M. Yassene

This study investigated the effect of styrene–butadiene‐rubber (SBR) latex/cement ratio as well as γ‐irradiation dose on physicomechanical properties of cement mortar. Specimens were prepared with a different SBR/cement mass ratio of 2.5, 5, 10, 15, and 20. Two curing methods were used: wet cure and dry cure. The best specimens were irradiated to doses of 10, 30, and 50 kGy. The compressive strength, total porosity, and bulk density were studied. The result indicated that the compressive strength, total porosity, and the bulk densities of the composites decrease with increase in the polymer cement ratios. In addition, it was observed that the compressive strength of irradiated polymer‐modified cement mortar composites was improved with the increase in the γ‐irradiation dose, and the compressive strength of mix‐cured samples was higher than those wet‐cured samples at any irradiation dose. X‐ray diffraction, thermogravimetric analysis, acid attack, and microstructure of SBR‐modified cement mortar were characterized. J. VINYL ADDIT. TECHNOL., 26:144–154, 2020. © 2019 Society of Plastics Engineers

In this study both uncalcined and calcined nanoclays (NC) were used as reinforcements for unsaturated polyester resin (UP).The nanoclay/unsaturated polyester composites (NC‐UP) were produced at various nanoclay contents (0, 3, 5, and 10 wt%) under the effect of two different doses of gamma rays 30 and 50 kGy. The mechanical and thermal properties of NC‐UP composites were studied. The compressive strength values of (NC‐UP) composites were found to increase with increasing the nanoclay content up to 5 wt%. Above 5 wt% of nanoclay, the compressive strength was decreased for the two different irradiation doses. Thermogravimetric analysis was carried out to determine the thermal stability and activation energy of the unsaturated polyester resin and its composites. The results also showed an enhancement in the thermal behavior of the composites with increasing nanoclay content. At a dose of 50 kGy, the addition of 5% nanoclay to unsaturated polyester increases the activation energy from 77 to 110 and 91 kJ/mol for uncalcined and calcined clay, respectively. The dispersion of nanoclay particles in polyester matrix was observed by scanning electron microscopy. The results clearly showed that, the calcination of the nanoclay content caused a desired effect on the final properties of NC‐UP composites as compared to the uncalcined nanocaly. The utilization of a higher gammairradiation dose (50 kGy) showed a good improvement in the thermal and mechanical properties as compared to the specimens irradiated at a dose of 30 kGy. The results are also confirmed by X‐ray diffraction analysis. POLYM. COMPOS., 39:3666–3675, 2018. © 2017 Society of Plastics Engineers

In this research, gamma radiation has been used to graft styrene and acrylic acid monomers onto marble (M) and granite (G) powder, with irradiation doses 30, 10 kGy, respectively. The grafted marble and granite powders were used as filler of epoxy composites. They added to an epoxy resin at 20, 60, and 100 wt% and then cured at room temperature. Ultrasonic velocities and attenuation measurements in epoxy composites at 4 MHz in the 25–300°C temperature range in addition to Fourier Transform Infrared (FTIR) analysis had been investigated. The ultrasonic compression wave velocity and the shear wave velocity measurements were performed using the pulse-echo technique, and then wecalculated elastic modulus, Young’s modulus, longitudinal and shear moduli, and Poisson’s ratio. In addition to attenuation at different temperatures of epoxy/granite composites, ultrasonic results indicated that the ultrasonic wave’s velocities V_L and V_s increased with the increase of (M, G) content and a linear relation was observed. Also, the attenuation of epoxy was stable and appeared to increase at temperature 385°C, while the addition M or G to epoxy composites increased the attenuation.